SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42d65673c635d91129b35850c88cc2231f39ec16224aa6cd2bc5da674dfeb559' 
  AND token = 'iuutVkddLaZlb7XJnc6fp1bvXN+/Hrn6sui7G1HxB64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}